/*
  SDL_mixer:    An audio mixer library based on the SDL library
  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.    In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
       claim that you wrote the original software. If you use this software
       in a product, an acknowledgment in the product documentation would be
       appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
       misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/* This file supports playing MP3 files with mpg123 */

#ifdef MUSIC_MP3_MPG123

#include "SDL_loadso.h"
#include "SDL_assert.h"

#include "music_mpg123.h"
#include "mp3utils.h"

#include <stdio.h>      /* For SEEK_SET */
#ifdef MPG123_HEADER
#include MPG123_HEADER
#else
#include <mpg123.h>
#endif
#ifdef _MSC_VER
typedef ptrdiff_t MIX_SSIZE_T;
#else
typedef ssize_t   MIX_SSIZE_T;
#endif


typedef struct {
    int loaded;
    void *handle;

    int (*mpg123_close)(mpg123_handle *mh);
    void (*mpg123_delete)(mpg123_handle *mh);
    void (*mpg123_exit)(void);
    int (*mpg123_format)( mpg123_handle *mh, long rate, int channels, int encodings );
    int (*mpg123_format_none)(mpg123_handle *mh);
    int (*mpg123_getformat)( mpg123_handle *mh, long *rate, int *channels, int *encoding );
    int (*mpg123_init)(void);
    mpg123_handle *(*mpg123_new)(const char* decoder, int *error);
    int (*mpg123_open_handle)(mpg123_handle *mh, void *iohandle);
    const char* (*mpg123_plain_strerror)(int errcode);
    void (*mpg123_rates)(const long **list, size_t *number);
#if (MPG123_API_VERSION >= 45) /* api (but not abi) change as of mpg123-1.26.0 */
    int (*mpg123_read)(mpg123_handle *mh, void *outmemory, size_t outmemsize, size_t *done );
#else
    int (*mpg123_read)(mpg123_handle *mh, unsigned char *outmemory, size_t outmemsize, size_t *done );
#endif
    int (*mpg123_replace_reader_handle)( mpg123_handle *mh, MIX_SSIZE_T (*r_read) (void *, void *, size_t), off_t (*r_lseek)(void *, off_t, int), void (*cleanup)(void*) );
    off_t (*mpg123_seek)( mpg123_handle *mh, off_t sampleoff, int whence );
    off_t (*mpg123_tell)( mpg123_handle *mh);
    off_t (*mpg123_length)(mpg123_handle *mh);
    const char* (*mpg123_strerror)(mpg123_handle *mh);
} mpg123_loader;

static mpg123_loader mpg123;

#ifdef MPG123_DYNAMIC
#define FUNCTION_LOADER(FUNC, SIG) \
    mpg123.FUNC = (SIG) SDL_LoadFunction(mpg123.handle, #FUNC); \
    if (mpg123.FUNC == NULL) { SDL_UnloadObject(mpg123.handle); return -1; }
#else
#define FUNCTION_LOADER(FUNC, SIG) \
    mpg123.FUNC = FUNC; \
    if (mpg123.FUNC == NULL) { Mix_SetError("Missing mpg123.framework"); return -1; }
#endif

#ifdef __APPLE__
    /* Need to turn off optimizations so weak framework load check works */
    __attribute__ ((optnone))
#endif
static int MPG123_Load(void)
{
    if (mpg123.loaded == 0) {
#ifdef MPG123_DYNAMIC
        mpg123.handle = SDL_LoadObject(MPG123_DYNAMIC);
        if (mpg123.handle == NULL) {
            return -1;
        }
#endif
        FUNCTION_LOADER(mpg123_close, int (*)(mpg123_handle *mh))
        FUNCTION_LOADER(mpg123_delete, void (*)(mpg123_handle *mh))
        FUNCTION_LOADER(mpg123_exit, void (*)(void))
        FUNCTION_LOADER(mpg123_format, int (*)( mpg123_handle *mh, long rate, int channels, int encodings ))
        FUNCTION_LOADER(mpg123_format_none, int (*)(mpg123_handle *mh))
        FUNCTION_LOADER(mpg123_getformat, int (*)( mpg123_handle *mh, long *rate, int *channels, int *encoding ))
        FUNCTION_LOADER(mpg123_init, int (*)(void))
        FUNCTION_LOADER(mpg123_new, mpg123_handle *(*)(const char* decoder, int *error))
        FUNCTION_LOADER(mpg123_open_handle, int (*)(mpg123_handle *mh, void *iohandle))
        FUNCTION_LOADER(mpg123_plain_strerror, const char* (*)(int errcode))
        FUNCTION_LOADER(mpg123_rates, void (*)(const long **list, size_t *number))
#if (MPG123_API_VERSION >= 45) /* api (but not abi) change as of mpg123-1.26.0 */
        FUNCTION_LOADER(mpg123_read, int (*)(mpg123_handle *mh, void *outmemory, size_t outmemsize, size_t *done ))
#else
        FUNCTION_LOADER(mpg123_read, int (*)(mpg123_handle *mh, unsigned char *outmemory, size_t outmemsize, size_t *done ))
#endif
        FUNCTION_LOADER(mpg123_replace_reader_handle, int (*)( mpg123_handle *mh, MIX_SSIZE_T (*r_read) (void *, void *, size_t), off_t (*r_lseek)(void *, off_t, int), void (*cleanup)(void*) ))
        FUNCTION_LOADER(mpg123_seek, off_t (*)( mpg123_handle *mh, off_t sampleoff, int whence ))
        FUNCTION_LOADER(mpg123_tell, off_t (*)( mpg123_handle *mh))
        FUNCTION_LOADER(mpg123_length, off_t (*)(mpg123_handle *mh))
        FUNCTION_LOADER(mpg123_strerror, const char* (*)(mpg123_handle *mh))
    }
    ++mpg123.loaded;

    return 0;
}

static void MPG123_Unload(void)
{
    if (mpg123.loaded == 0) {
        return;
    }
    if (mpg123.loaded == 1) {
#ifdef MPG123_DYNAMIC
        SDL_UnloadObject(mpg123.handle);
#endif
    }
    --mpg123.loaded;
}


typedef struct
{
    struct mp3file_t mp3file;
    int play_count;
    int freesrc;
    int volume;

    mpg123_handle* handle;
    SDL_AudioStream *stream;
    unsigned char *buffer;
    size_t buffer_size;
    long sample_rate;
    off_t total_length;
    Mix_MusicMetaTags tags;
} MPG123_Music;


static int MPG123_Seek(void *context, double secs);
static void MPG123_Delete(void *context);


static int mpg123_format_to_sdl(int fmt)
{
    switch (fmt) {
        case MPG123_ENC_SIGNED_8:       return AUDIO_S8;
        case MPG123_ENC_UNSIGNED_8:     return AUDIO_U8;
        case MPG123_ENC_SIGNED_16:      return AUDIO_S16SYS;
        case MPG123_ENC_UNSIGNED_16:    return AUDIO_U16SYS;
        case MPG123_ENC_SIGNED_32:      return AUDIO_S32SYS;
        case MPG123_ENC_FLOAT_32:       return AUDIO_F32SYS;
        default:                        return -1;
    }
}

/*#define DEBUG_MPG123*/
#ifdef DEBUG_MPG123
static const char *mpg123_format_str(int fmt)
{
    switch (fmt) {
#define f(x) case x: return #x;
        f(MPG123_ENC_UNSIGNED_8)
        f(MPG123_ENC_UNSIGNED_16)
        f(MPG123_ENC_SIGNED_8)
        f(MPG123_ENC_SIGNED_16)
        f(MPG123_ENC_SIGNED_32)
        f(MPG123_ENC_FLOAT_32)
#undef f
    }
    return "unknown";
}
#endif

static char const* mpg_err(mpg123_handle* mpg, int result)
{
    char const* err = "unknown error";

    if (mpg && result == MPG123_ERR) {
        err = mpg123.mpg123_strerror(mpg);
    } else {
        err = mpg123.mpg123_plain_strerror(result);
    }
    return err;
}

/* we're gonna override mpg123's I/O with these wrappers for RWops */
static MIX_SSIZE_T rwops_read(void* p, void* dst, size_t n)
{
    return (MIX_SSIZE_T)MP3_RWread((struct mp3file_t *)p, dst, 1, n);
}

static off_t rwops_seek(void* p, off_t offset, int whence)
{
    return (off_t)MP3_RWseek((struct mp3file_t *)p, (Sint64)offset, whence);
}

static void rwops_cleanup(void* p)
{
    (void)p;
    /* do nothing, we will free the file later */
}


static int MPG123_Open(const SDL_AudioSpec *spec)
{
    (void)spec;
    if (mpg123.mpg123_init() != MPG123_OK) {
        return Mix_SetError("mpg123_init() failed");
    }
    return 0;
}

static void *MPG123_CreateFromRW(SDL_RWops *src, int freesrc)
{
    MPG123_Music *music;
    int result, format, channels, encoding;
    long rate;
    const long *rates;
    size_t i, num_rates;

    music = (MPG123_Music*)SDL_calloc(1, sizeof(*music));
    if (!music) {
        SDL_OutOfMemory();
        return NULL;
    }
    music->volume = MIX_MAX_VOLUME;

    if (MP3_RWinit(&music->mp3file, src) < 0) {
        SDL_free(music);
        return NULL;
    }
    meta_tags_init(&music->tags);
    if (mp3_read_tags(&music->tags, &music->mp3file, SDL_TRUE) < 0) {
        SDL_free(music);
        Mix_SetError("music_mpg123: corrupt mp3 file (bad tags.)");
        return NULL;
    }

    /* Just assume 16-bit 2 channel audio for now */
    music->buffer_size = music_spec.samples * sizeof(Sint16) * 2;
    music->buffer = (unsigned char *)SDL_malloc(music->buffer_size);
    if (!music->buffer) {
        MPG123_Delete(music);
        SDL_OutOfMemory();
        return NULL;
    }

    music->handle = mpg123.mpg123_new(0, &result);
    if (result != MPG123_OK) {
        MPG123_Delete(music);
        Mix_SetError("mpg123_new failed");
        return NULL;
    }

    result = mpg123.mpg123_replace_reader_handle(
        music->handle,
        rwops_read, rwops_seek, rwops_cleanup
    );
    if (result != MPG123_OK) {
        Mix_SetError("mpg123_replace_reader_handle: %s", mpg_err(music->handle, result));
        MPG123_Delete(music);
        return NULL;
    }

    result = mpg123.mpg123_format_none(music->handle);
    if (result != MPG123_OK) {
        Mix_SetError("mpg123_format_none: %s", mpg_err(music->handle, result));
        MPG123_Delete(music);
        return NULL;
    }

    mpg123.mpg123_rates(&rates, &num_rates);
    for (i = 0; i < num_rates; ++i) {
        const int channels = (MPG123_MONO|MPG123_STEREO);
        const int formats = (MPG123_ENC_SIGNED_8 |
                             MPG123_ENC_UNSIGNED_8 |
                             MPG123_ENC_SIGNED_16 |
                             MPG123_ENC_UNSIGNED_16 |
                             MPG123_ENC_SIGNED_32 |
                             MPG123_ENC_FLOAT_32);

        mpg123.mpg123_format(music->handle, rates[i], channels, formats);
    }

    result = mpg123.mpg123_open_handle(music->handle, &music->mp3file);
    if (result != MPG123_OK) {
        Mix_SetError("mpg123_open_handle: %s", mpg_err(music->handle, result));
        MPG123_Delete(music);
        return NULL;
    }

    result = mpg123.mpg123_getformat(music->handle, &rate, &channels, &encoding);
    if (result != MPG123_OK) {
        Mix_SetError("mpg123_getformat: %s", mpg_err(music->handle, result));
        MPG123_Delete(music);
        return NULL;
    }
#ifdef DEBUG_MPG123
    printf("MPG123 format: %s, channels: %d, rate: %ld\n",
            mpg123_format_str(encoding), channels, rate);
#endif

    format = mpg123_format_to_sdl(encoding);
    SDL_assert(format != -1);
    music->sample_rate = rate;

    music->stream = SDL_NewAudioStream((SDL_AudioFormat)format, (Uint8)channels, (int)rate,
                                       music_spec.format, music_spec.channels, music_spec.freq);
    if (!music->stream) {
        MPG123_Delete(music);
        return NULL;
    }

    music->total_length = mpg123.mpg123_length(music->handle);

    music->freesrc = freesrc;
    return music;
}

static void MPG123_SetVolume(void *context, int volume)
{
    MPG123_Music *music = (MPG123_Music *)context;
    music->volume = volume;
}

static int MPG123_GetVolume(void *context)
{
    MPG123_Music *music = (MPG123_Music *)context;
    return music->volume;
}

static int MPG123_Play(void *context, int play_count)
{
    MPG123_Music *music = (MPG123_Music *)context;
    music->play_count = play_count;
    return MPG123_Seek(music, 0.0);
}

static void MPG123_Stop(void *context)
{
    MPG123_Music *music = (MPG123_Music *)context;
    SDL_AudioStreamClear(music->stream);
}

/* read some mp3 stream data and convert it for output */
static int MPG123_GetSome(void *context, void *data, int bytes, SDL_bool *done)
{
    MPG123_Music *music = (MPG123_Music *)context;
    int filled, result;
    size_t amount = 0;
    long rate;
    int channels, encoding, format;

    if (music->stream) {
        filled = SDL_AudioStreamGet(music->stream, data, bytes);
        if (filled != 0) {
            return filled;
        }
    }

    if (!music->play_count) {
        /* All done */
        *done = SDL_TRUE;
        return 0;
    }

    result = mpg123.mpg123_read(music->handle, music->buffer, music->buffer_size, &amount);
    switch (result) {
    case MPG123_OK:
        if (SDL_AudioStreamPut(music->stream, music->buffer, (int)amount) < 0) {
            return -1;
        }
        break;

    case MPG123_NEW_FORMAT:
        result = mpg123.mpg123_getformat(music->handle, &rate, &channels, &encoding);
        if (result != MPG123_OK) {
            return Mix_SetError("mpg123_getformat: %s", mpg_err(music->handle, result));
        }
#ifdef DEBUG_MPG123
        printf("MPG123 format: %s, channels: %d, rate: %ld\n",
                mpg123_format_str(encoding), channels, rate);
#endif

        format = mpg123_format_to_sdl(encoding);
        SDL_assert(format != -1);

        if (music->stream) {
            SDL_FreeAudioStream(music->stream);
        }

        music->stream = SDL_NewAudioStream((SDL_AudioFormat)format, (Uint8)channels, (int)rate,
                                           music_spec.format, music_spec.channels, music_spec.freq);
        if (!music->stream) {
            return -1;
        }
        music->sample_rate = rate;
        break;

    case MPG123_DONE:
        if (amount > 0) {
            if (SDL_AudioStreamPut(music->stream, music->buffer, (int)amount) < 0) {
                return -1;
            }
            break;
        }
        if (music->play_count == 1) {
            music->play_count = 0;
            SDL_AudioStreamFlush(music->stream);
        } else {
            int play_count = -1;
            if (music->play_count > 0) {
                play_count = (music->play_count - 1);
            }
            if (MPG123_Play(music, play_count) < 0) {
                return -1;
            }
        }
        break;
    default:
        return Mix_SetError("mpg123_read: %s", mpg_err(music->handle, result));
    }
    return 0;
}
static int MPG123_GetAudio(void *context, void *data, int bytes)
{
    MPG123_Music *music = (MPG123_Music *)context;
    return music_pcm_getaudio(context, data, bytes, music->volume, MPG123_GetSome);
}

static int MPG123_Seek(void *context, double secs)
{
    MPG123_Music *music = (MPG123_Music *)context;
    off_t offset = (off_t)(music->sample_rate * secs);

    if ((offset = mpg123.mpg123_seek(music->handle, offset, SEEK_SET)) < 0) {
        return Mix_SetError("mpg123_seek: %s", mpg_err(music->handle, (int)-offset));
    }
    return 0;
}

static double MPG123_Tell(void *context)
{
    MPG123_Music *music = (MPG123_Music *)context;
    off_t offset = 0;
    if (!music->sample_rate) {
        return 0.0;
    }
    if ((offset = mpg123.mpg123_tell(music->handle)) < 0) {
        return Mix_SetError("mpg123_tell: %s", mpg_err(music->handle, (int)-offset));
    }
    return (double)offset / music->sample_rate;
}

/* Return music duration in seconds */
static double MPG123_Duration(void *context)
{
    MPG123_Music *music = (MPG123_Music *)context;
    if (music->total_length < 0) {
        return -1.0;
    }
    return (double)music->total_length / music->sample_rate;
}

static const char* MPG123_GetMetaTag(void *context, Mix_MusicMetaTag tag_type)
{
    MPG123_Music *music = (MPG123_Music *)context;
    return meta_tags_get(&music->tags, tag_type);
}

static void MPG123_Delete(void *context)
{
    MPG123_Music *music = (MPG123_Music *)context;

    meta_tags_clear(&music->tags);
    if (music->handle) {
        mpg123.mpg123_close(music->handle);
        mpg123.mpg123_delete(music->handle);
    }
    if (music->stream) {
        SDL_FreeAudioStream(music->stream);
    }
    if (music->buffer) {
        SDL_free(music->buffer);
    }
    if (music->freesrc) {
        SDL_RWclose(music->mp3file.src);
    }
    SDL_free(music);
}

static void MPG123_Close(void)
{
    mpg123.mpg123_exit();
}

Mix_MusicInterface Mix_MusicInterface_MPG123 =
{
    "MPG123",
    MIX_MUSIC_MPG123,
    MUS_MP3,
    SDL_FALSE,
    SDL_FALSE,

    MPG123_Load,
    MPG123_Open,
    MPG123_CreateFromRW,
    NULL,   /* CreateFromFile */
    MPG123_SetVolume,
    MPG123_GetVolume,
    MPG123_Play,
    NULL,   /* IsPlaying */
    MPG123_GetAudio,
    NULL,   /* Jump */
    MPG123_Seek,
    MPG123_Tell,
    MPG123_Duration,
    NULL,   /* LoopStart */
    NULL,   /* LoopEnd */
    NULL,   /* LoopLength */
    MPG123_GetMetaTag,
    NULL,   /* GetNumTracks */
    NULL,   /* StartTrack */
    NULL,   /* Pause */
    NULL,   /* Resume */
    MPG123_Stop,
    MPG123_Delete,
    MPG123_Close,
    MPG123_Unload
};

#endif /* MUSIC_MP3_MPG123 */

/* vi: set ts=4 sw=4 expandtab: */
